Optical Rings and Hybrid Mesh Rings Optical Networks draft-papadimitriou-optical-rings-00.txt. Dimitri Papadimitriou - Alcatel

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1 Optical Rings and Hybrid Mesh Rings Optical Networks draft-papadimitriou-optical-rings-00.txt Dimitri Papadimitriou - Alcatel

2 Rationale for Optical Rings All-Optical switches for metro DWDM networks all-optical revolution comes from the metro networks since not impacted by distance (~ 800 km) Metro networks high bandwidth needs (~ 1Tb/s) Coarser granularity than SDH/Sonet required who needs a 2 Mb LL-based management today? Transparent to the client signal framing (A / Sync) Ethernet - ATM - FR - SDH/Sonet are perfect clients Dynamic resource allocation - resource optimization distributed and flexible bandwidth allocation Need for a flexible wavelength assignment / conversion avoid wavelength blocking problem Low-cost protection (Uni- or Bi-directional) re-usable protection capacity

3 Scope - Introduction Optical rings : IP-over-Optical Metro networks Optical Resilient Packet Ring Signalling and TE-Routing extensions must be uniquely defined - interoperability at boundary Protection mechanism The first SDH/Sonet addedvalue : provide the same fast protection functionality without known impairments Flexible ring design: Dynamic Ring Configuration QoS provide distributed TE - CoS mechanisms (Dynamic Ring Resource Allocation) Other PM to be defined - signal quality monitoring at optical level The second SDH/Sonet added-value : to be defined (on-going work)

4 Optical Network Topology Mesh and transparent optical network including OXC OXC ports: Lambda-Switch Capable (LSC) interfaces interface including WC capability (tunable lasers) interface including DWDM capabilities WC and DWDM could be external Distributed IP Control-plane (internal or external) Signalling transport IF/OB (moving to IF/IB) Signalling protocol based GMPLS OXC A Signalling Signalling Signalling OXC B OXC I OXC J...

5 Optical Ring Emulation Dynamic configuration of logical rings on top of meshed optical topology including OXC (not only O-ADM) Ring Emulation requires: OXC switching matrix provides: Add - Drop - D&C - Protection (SNCP) functions Working wavelengths (on shared links) belongs to only one ring at a time Protection wavelengths (on shared links) shared between rings for protection Dynamic Ring Configuration: Ring Identification Ring Protection Type Ring Architecture

6 OXC as O-ADM DeMux Mux Cross - Bar Mux DeMux OUT OCh Add - Drop IN OCh DeMux Mux OUT OCh IN OCh

7 Optical Ring Topology OXC 1 OXC 2 OXC 6 Signalling Ring OXC 3 OXC 5 OXC 4 OXC 1 - IP Address1 OXC 2 - IP Address OXC 6 - IP Address6

8 Optical Ring Inter-Connection Each node belongs to a given ring except boundary OXC (B, D, E, F, H) OXC A Optical Meshed Topology OXC B 5 OXC C Ring 1 Ring 2 OXC D OXC E OXC F Ring 4 Ring 3 OXC G OXC H OXC I Ring Cover: set of closed paths covering all links in the meshed optical network at least once (every node belongs to at least one ring)

9 Inter-ring Routing Considerations Node E belongs to 4 rings: Ring 1 Node B, E Ring 2 Node E Node E, D Node E, F Node E Ring 4 Node E, H Ring 3 Node E provides 6 inter-connections (shortest path) Additional information required such as working and protection ring load to be shared between rings Otherwise: node E overloaded and single point of failure

10 Inter-ring Routing Considerations Node E failure: Ring 1 Node B Ring 2 Node D Node F Ring 4 Node H Ring 3 Does Ring 2 and Ring 4 provide enough capacity? Additional information required such as working and protection ring load to be shared between rings Otherwise: node E overloaded and single point of failure

11 Optical Rings vs Mesh Protection Protection Type Dedicated Line Shared Line Dedicated Path Shared Path Mesh Protection 1+1-1:1 1:N (M:N) 1+1-1:1 1:N (M:N) Ring Protection (ITU-T) OMS-DPRing (O-ULSR) OMS-SPRing (O-BLSR) OCh-DPRing (O-UPSR) OCh-SPRing (O-BPSR) Ring Protection (ITU-T) OMS-DPRing (O-ULSR) OMS-SPRing (O-BLSR) OCh-DPRing (O-UPSR) OCh-SPRing (O-BPSR) Protection Mechanism 1+1 dedicated fiber link (or wavelength) M:N shared fiber link (or wavelength) 1+1 dedicated LSP segment protection M:N shared LSP segment protection

12 Dynamic Ring Configuration (DRC) Emulated ring determined by exchanging Ring ID (32-bit field) Ring Virtual IP Address (32-bit field) Loopback IP Address per OXC and per contiguous ring Ring Protection Type (8-bit field) Ring Protection Policy (8-bit field): Strategy - Scheme - Priority SRLG Identifiers [draft-many-inference-srlg-00.txt] Ring Metric (bootstrap initial DRRA) Ring Metric Absolute weight: # Nodes (non-adjacent nodes) Capacity: # Incoming - # Outgoing - # AD Channels Maximum Restoration Time (MRT)

13 Dynamic Ring Resource Allocation (DRRA) Related to Intra-Ring Traffic Engineering Required to dynamically setup LSP segments Based on classical link TE information Ring Metric Ring Weight: working and protection ring Working RW = ( 1 / [ # Nodes ] ) x 100 x r1 Protection RW = ( [ Working RW ] ) x r2 Ring Load (per time unit): working and protection ring Working RL = ( [ # Working LSP ] / [ Ring Capacity ] x 100 ) x r3 Protection RL = ( [ # Protection LSP ] / [ Ring Capacity ] x 100 ) x r4 Maximum Restoration Time: MRT = MRT[N] x 100 x r5 if MRT[N] > MRT[N-1] then maxmrt[n] = MRT[N-1] + ( k1 x MRT[N-1] ) and MRT[N] = mean [ maxmrt[n] ; MRT[N-1] ] if MRT[N] < MRT[N-1] then minmrt[n] = MRT[N-1] - ( k2 x MRT[N-1] ) and MRT[N] = mean [ MRT[N-1] ; minmrt[n] ]

14 Inter-Ring Traffic Engineering Inter-ring TE LSA = TE Summary LSA (Opaque LSA Type-10) Generated at ring boundary nodes Carries TE Attributes including Ring Count Maximum Reservable Bandwidth Minimum Reservable Bandwidth Delay Resource Class/Coloring Inter-Ring TE Metric Inter-Ring TE Metric Weighted sum of ring TE metrics (from Ring[1] to Ring[N]) IR-TE Metric = k[1] x Ring TE Metric[1] + k[2] x Ring TE Metric[2]... k[n] x Ring TE Metric[N]

15 Inter-Ring Traffic Engineering Optical Meshed Topology Source OXC A Tunnel 1 OXC B 5 OXC C OXC J Ring 1 Ring 2 Ring 3 OXC D OXC E OXC F OXC K Ring 6 Ring 5 Ring 4 OXC G OXC H Tunnel 2 OXC I Tunnel 3 OXC L Destination Explicit Route [Source] : Node A - Node E - Node I - Destination Explicit Route [A] : Node A - Tunnel 1 - Node E - Node I - Destination Complete Route : Node A - T1 - Node E - T2 - Node I - T3 - Node L - Destination

16 Signalling Extensions Signaled Protection (1:1-1:N - M:N) splitting of the signalling messages draft-many-optical-restoration-00.txt Non-Signaled Protection (1+1) 1+1 Protected LSP segment Optical signal is physically split Signalling message is logically duplicated draft-poj-optical-multicast-00.txt Inter-ring Signalling extensions Drop-and-continue (redundant inter-ring connection) Optical signal is physically split Physical Point-to-multipoint connection Virtual Point-to-multipoint LSP segment

17 Conclusion: Conclusion - Proposal Transparent and All-optical rings concepts can be extended to IP over Optical Resilient Packet Rings Signaled Protection using IP-based O-APS like protocol or by extending current signalling protocols (CR-LDP - RSVP-TE) Ring concept is applicable with minor extensions to TE extended routing IGP protocols Inter-ring connectivity (drop-and-continue) key issue wrt optical network survivability DRC and DRRA mechanisms provide required flexibility while optimizing ring resources and facilitating their management Proposal: Accept the proposed contribution as an IPoRPR Protection and TE-Routing document